Development on the Yafray 0.0.9 source code was stopped in July 2006 because it was pretty much exhausted, and it did not allow for further changes and additions in a sensible way. Nobody is working on the YafRay 0.0.9 source code neither on the built-in Blender exporter code.

The new development branch consist in a complete rewritting of the YafRay source code and it is called YafaRay, you can find more info in these links: